Machine tool



L. F. POLK- MACHINE TOOL Sept. 25, 1945 Filed April 26, 1943 Patented Sept. 25, 1945 MACHINE TOOL Louis F. Polk, Dayton, Ohio, assignor to The Shefiield Corporation, Dayton, Ohio, a corporation of Ohio Application April 26, 1943, Serial No. 484,580

18 Claims. (Cl. 12511) This invention relates to grinding machines and more particularly to means fortruing or surfacing the grinding wheel of such a machine.

One object of the invention is the provision,

in a grinding machine, of a grinding wheel truin device including a rotatable crusher wheel having supporting and control means whereby the crusher wheel is moved automatically into con.- tact with the grinding Wheel and is then given a.

comparatively slow feeding movement into the grinding wheel fortruing the surface of the grinding wheel.

Another object is the provision of a rotatable crusher wheel. adapted to operate in peripheral contact withthe grindin wheelto-truethe surface of the grinding wheel, in combinationwith an adjusting motor which operates to movethe crusher support in a controlled manner so that the crusher wheel is brought rapidly into a pre-;-.

determined position in which it contacts with the grinding wheel and is then fed into t'hegrinding wheel for effective crushing action. I

Another, object is the provision of a, crusher wheel support carried by the frame of agrinder, and a motor which automatically controls ase- .quence of operations, first lowering .the crushing wheel into contact-with the grinding wheel, then startin the grinding wheel into operation-thenfeeding the crusher wheel slowly towards the axis of the grinding wheel} and then backing off the crusher wheel. l v

Other objects and advantagesof the invention will be apparent from the following description, the appended claims, and the accompanying drawing, in which, I

Fig. l is a side elevation, partly in section, showing the upper portion of the machine .frameof a grinder, and the adjusting and operating means for the crushersupport;

Fig. 2 is a vertical section on a reduced scale, on the line 22 of Fig.1;

Fig. 3 is a view showing the arrangement of the double lift cam;

driving means by which it is operated at comparatively slow speed.

Referring more particularly to the drawing, in which the same reference numerals designate like parts in the several views, ll] designates the frame of a grinding machine, having a rotatable grinding wheel ll arranged for rotation in the frame. Thewheel l I is rotated at comparatively high speed by a suitable driving motor which hasnot been illustrated since a power drive of a grinding wheel is very well known in the art. Where the grinding wheel is stationary, the frame-I0 forms a part'of the fixed main frame structure of the grinding machine, although if the grinding wheel is axially movable in operation, or is movable towards and from thework, the frame [0 will constitute the movable supportfor the wheel as is well known in the art. The grinding wheel as herein shown is one having a series of annular ribs so formed as to grind threads as the workpiece is moved axially with relationto the grinding wheel. 7

The grinding wheel after a period of use should be trued, and this truing, operation ha'sbeen accomplished by moving diamonds along the wheel surface to give the desired contour, or by manually moving a rotatablemetal crusher having annularribs that give the desired contour on the bracket 1 3 and normally when the grinding wheel is in use, the crusher l2 isv arranged some little distance. radially outwardly from the grinding wheel. This crushermay. be of suitable hard metal so that when This pressed against the grind- Fig.4 is a detail of the-reed ratchet operating mechanism;

Fig. 5 is a detail its switch;

Fig. 6 is a. detail showing the clutch retaining pawl and cam; I 7 Fig. '7 is a detail showing the ratchet wheel and the clutchrelease pawl;

Fig. 8 is a diagrammatic showing of the electrical connections; and

Fig. 9 is a sectional partly diagrammatic view showin the grindin wheel, its support, and the showing the timing cam and ing wheel, with the grinding wheel rotatingat comparatively slow speed, the crusher will be revolved by the grinding wheel and will press or crush the desired surface on the grinding wheel to bring the latter back to a true form.

The crusher wheel supporting bracket I3 is slid-ably guided in side walls 15 of frame Land is adjustably secured to a slida'ble. plate [6 carrying'a head [1 which'is connected by adjusting screw l8 to a nut 19 fixed on the supporting bracket. The plate I6 is guided for movement towards and from the axis of the grinding wheel I I between the supporting bracket [3 and the wall portion 2| of the frame, and it projects up through an opening in the upper portion of the frame which is large enough to receive the head l1 although the latter. is normally arranged above the frame as shown in Fig. 1. The upper portion of the screw l8 has a square head 22 so that it can be turned by a wrench to raise or lower the supporting bracket l3 with respect to the head I! and the plate l6. A scale 30 on the head I! and a cooperating post 30 on the frame I!) showthe position of the head and can be used to determine if the head is at its lowermost position.

As shown, the crusher is arranged up above the grinding wheel, andthemovementsor the crusher wheel support take place vertically and transversely of the axis of the grinding wheel.

The wall portion 2| of the frame has a vertical. i slot that receives a bar 23, fixed to the .plateporting b acket will alsoimove up and down with the plate l6. r

The cams 2'8 and 29 are power operated in an automatic manner to advance the crusher towards the grinding Wheel at a comparatively rapid rate, and thenrhold .the ,plate 16 and the head I! stationary during the crushing ,opera ,r

tion. After the crushing operation is completed plate 1.6 and head I! are moved up to their rig- .inal positions by the cams sov that the crusher is spaced from the grinding wheel. After the crusher has been'lowered by the cams 28. an -29, nd while the plate l6 remains stationary in its lowered 1: osition,. th adjusting, screw 18 is automaticallyturnedso that the crusher will be slowly fed into the grinding wheel, and the actual crushing. operation takes .place at a con,-

trolled rate. "The extent -of movement given :to 'the crusher wheel supportingbracket'by the adjusting screw [8 may be such as vto .moveithe crusher. a ,few thousandths of an'inch while "the grinding. wheel rotatesithrough several revolutions, the rotation of the grindingwheel rotating the crusher wheel itself.

The construction herein shownas apreferred embodiment of the mechanism for automatically moving the crusher wheel.- during the crushing operation will now be ,further described. The frame 10 carries an. adjusting motor-31, prefer- .ably an electric motor having a. gear reducing drive 32 to ashort shaft. 33. ;Fixed on the shaft 13.3 Zisa ratchet wheel .34 adapted to ,becoupledto the drive plate 35 -by .a pawlflfi pivoted-arts?! on the drive plate. .A spring 38 tends to connect the. .pawl to the drive plate althoueha-clutch release pawl 39 controlled Joy-a spring flfl ;nor- ;mally holds the upwardly extending portion of pawl 36 towards the right asyiewedrin Fig. 7 and keeps the pawl 36 free from the ratchet-wheel. By energizing a relay orzsolenoid 42;, the-freeend ofth'e clutch release pawl is pulled. down and-this I frees the ,paw1i'36 .so that the ratchet 'wheel :is

placed :in driving connection with @the :drive :plate 35. iThe drive :platei35 can'be rotated through one revolution and then its cam projection '43 'co'mes against the finger 44 on the end of the clutch release pawl and this finger positively stops the rotation of the'driveplate '35. Just before; this 'takes'place-however the upwardly projecting portion of. the pawl 36 comes against the finger '44 andis forced out of engagement Cit with the ratchet wheel to disconnect the driving force from the drive plate.

The drive plate 35 is fixed on a shaft 46 rotati ably journaled in bearing portions 4'! of the frame In. The shaft 46 is also provided with a cam 48 which controls a clutch retaining pawl 49 serving to open and close the motor switch 5| and thus control the starting and stopping of the adjusting motor'3l.

Another cam 52 on shaft 46 serves as a timer to control a switch 53 which controls a motor 56 'which is employed during the crushing operation to. provide a comparatively slow speed drive for the grinding wheel H. When the switch 53 is closedit operates through a relay 54 to close switch 55, see Fig. 8, and cause the'grinding wheel I l to rotate at comparatively slow speed.

Cam 5'! on shaft 46 controls the feed screw l8 through lever 58, the upper end of which bears against a vertically extending plate portion 59 of a ratchetieed yoke 66 arran ed ,for; rotation .onthe .upper portion of the .feed screw I8. The feed yoke, is thus given anoscillatory movement under the control of the feeding cam-51,. The iced yoke pivotally carries a feed pawl-ratchet 61 which operates ag inst, the ratchet .Wheel .52 ,fixedon'the feed screw l8. .Ijhe Afeed movement ta es. place as the ratche pawlis carried to the right asviewed in Fig. 2, .to producea lowering movement of the crusher wheelbracketglj with respect to thep'late l6 and the, head 11.

Suitable means is provided for-adjusting the amount of feed movement imparted to the screw I 8, t p mi movementoi thecnlsher wheelinto the rindi Wheel to an extent dependent upon the wheel characteristics, the pitch spacing'of the wheel ribs, etc. For this purpose, the lever .58 is provided withan extensible arm Iormed of adiusta ly interconnected arm .sectionsflll and Ll, one of which is slotted as indicated atlZ. ,.A

isficlllingb-Qlt screw "'3 ope ablenalongthe slot '12 holds thejtwo annsections ri id y to. one another and p rmits adjustmentiin- ,theilen th f thearrncand consequently p rmits adjustment in the amount of .movement'imparted to the. plate portion, 59 for. any rotation of the. cam 1'51... The

amount ofmovement f the plate. por on 59 may also be controlled, for varying. the amountjof feeding movement, by la erally diusting he upper end portion 14. of the leverj58, withzres pect to the arm section II, the upper portionpf arm section 1| bein turnedout as shown in Fig. 1 and adjustably supporting the f00tpcrti n 5 f the portion 14 as by means .of a securing screw "16 operable along a slot in the outturnedupper portion of the arm section ll. 'Thisprovides -.variation in the distance between the axis of the screw J8. and the point of. application of force to the'plate portion 59. As will be noted inFig. 1,.means is also provided for indicating, to the operator, the amount of feeding .movement ,imparted to the screw I8, this means comprising index marks" on a dial 16 whichisfixed to the screwl8 by means of a set screw 19, The indications or scale markings 11 act inconjunction with an index mark .80 on the nonrotatable 'head 11.

As will now bev apparent, when the operator "desires to crush or true the grinding wheel, and

.the' .device has previously been properly. set up, he closes the starting switches shown. at 64 in Fig. 8, and this energizes the solenold fl from the power source 65. The solenoid pulls the clutch release pawl,39 so that its finger 44, .releases pawl 36 and permits that pawl to drop ingrees.

to the ratchet wheel 34. At'the same time lever,

39 is moved, it closes the motor switch 5I so that the motor 3| is energized through connection 66 to source 65. In circuit with motor 3| is a normally closed stopping switch 68. ratchet wheel thus starts turning, carrying the drive plate 35 along with it, and during the 360 movement of the drive plate the following operations take place successively.

First, the double plate cam 28 and 29 causes the crusher wheel support to be lowered until the crusher wheel is engaging the grinding wheel I I. This is completed in about 50 travel of shaft 46. Then the timing cam 52 closes switch 53 to cause rotation of the motor 56 to operate the grinding wheel at a comparatively slow speed, through about 200 movement of the feeding cam or from point a to point D, see Fig. 4, so that the ratchet pawl BI turns the ratchet wheel 62 slowly and thus slowly rotates the adjusting screw I8 in a positive manner during the effective crushing operation, the movements of the adjusting screw causing the crusher wheel to be forced positively and in a controlled manner against the crusher wheel and exert the desired pressure in the crushing operation. The arrangement is such that the grinding wheel rotates through several revolutions as the cam 51 rotates about 200. de-

Between the points b and c on the cam 51 the cam surface is concentric with its axis so no feed movement of the screw I8 is produced as the grinding wheel rotates one or two revolutions before retracting the crusher. After the feed-in of the crusher wheel stops and as the point e on cam n 51 comes opposite the roller on lever 58, the double plate lift cam 28 and 29 moves the whole crusher support upwardly, comparatively rapid- 1y, without however disturbing the adjustment between the screw I8 and the crusher supporting bracket. During this upward movement of the crusher wheel support, the arm 58 is spring returned in a counter-clockwise direction ready for the next ratcheting step. Before the upward The I When a new wheel, that has not been previously grooved, is applied to the machine, the'cr'usher wheel supporting bracket I3 is moved up far enough, by turning the screw I8, so it will not quite touch the grinding wheel when the head I! is lowered by the crusher wheel adjusting motor. The crusher adjusting motor is then started and when a resulting cycle is only partly completed, the switch 68 is opened, to stop the-adjusting motor 3| at a time when the crusher pleted, leaving the crushing wheel finally in its elevated position and ready for a succeeding crushing cycle.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to the precise form herein disclosed, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A grinding machine having a. frame carrying a rotatable grinding wheel and driving means therefor; a rotatable crusher wheel, a crusher wheel support movably carried by the frame, a feed screw for positively controlling the position of said support, an adjusting motor, and means operable to cause the adjusting motor to move wheel, then to operate said feed screw to feed the crusher support slowly through a predetermovement of the crusher wheel support is completed the motor which drives the grinding wheel during the crushing operation is deenergized under the control of the timing cam 52. The cam shaft then completes its 360 of travel and is latched at the completion of its travel.

Just before it is latched the clutching pawl 49 drops into a notch in cam 48 and opens the motor switch 5|. These several operations take place successively at the proper times so that the crusher will be brought against the grinding wheel when the grinding wheel is not rotated, and after the grinding wheel starts to move, the in-feeding movements of the crusher are carried out automatically in a controlled manner. When a second crushing cycle takes place, there will of course be a further in-feeding movement causing a, further adjustment in the relative positions of the crusher bracket I3 and the plate I6.

After the wheel has been considerably reduced in diameter and it is necessary to replace it with a new wheel the feed ratchet pawl 6| may be held out of engagement with ratchet wheel 62,;

and the adjusting screw I8operated manually by a wrench applied to its square head 22 so that the bracket I3 is moved upwardly to a desired initial position so coordinated with the diameter of the new grinding wheel that it will contact the grinding wheel when it is lowered by the cam 2829. The adjusting screw I8 can be turned manually at any time'during the crushing operation if that should be desired.

mined distance to the grinding wheel and then retract it from the grinding wheel.

2. A grinding machine having a frame carrying a rotatable grinding wheel and. driving means therefor, a rotatable crusher wheel, a crusher wheel support movably carried by the frame, an adjusting motor, means operable to cause the adjusting motor to move the crusher wheel support rapidly to the grinding wheel, then to feed said support slowly to the grinding wheel and then retract it from the grinding Wheel, and means for initiating slow speed rotation of the grinding wheel'before the slow feeding movement of the crusher wheel support takes place.

3. In a grinding machine having a frame carrying a rotatable grinding wheel and driving means therefor, a rotatable crusher wheel, a crusher wheel support movably carried by the machine frame, a, carrier movably mountedon the frame and carrying the crusher wheelsupport, adjusting mechanism including an adjusting motor for varying the position of said support on the carrier, and means operated by said motor for moving the carrier to move said crusher wheel to the grinding wh'eel.

4. In a grinding machine having a frame carrying a rotatable grinding wheel and driving means therefor, a rotatable crusher wheel, a crusher wheel support movably carried by the machine frame, a carrier movably mounted on the frame and carrying the crusher wheel support, adjusting mechanism for varying the position of said support on the carrier and including means operable to move the carrier rapidly towards the grinding wheel, then maintain the carrier in a predetermined position fora timeand then retractiit from the grinding wheel, and means for automatically feeding the crusher wheel towards the grinding wheel while the carrier remains in .said predetermined position.

5. Av grinding machine having a frame car- .rying a rotatable grinding wheel anddrive mean therefor, a rotatable crusher wheel, a crusher wheel support movably carried by the frame, a plurality of adjusting 'mechanisms for said suppert,-an adjusting motor for operating said mechanisms, ,and means for automatically operating said mechanisms sequentially by the adjusting ;motor:to brin the crusher wheel into engage Jnent with the grinding wheel and then slowly feed the crusher wheel into the grinding wheel.

.6.-,-A grinding machine having a, frame carry- ;ing airotatable grinding wheel and drive means ,therefor, a rotatable crusher wheel, a crusher wheelisupport movably carried by the frame, ad- .justingmechanism for said support, an adjusting motor, a one revolution clutch between the adjusting motor and the adjusting mechanism,

' and means driven by said motor for positively ,moving the crusher wheel supportto engage the crusher, wheel with the grinding wheel and then 1-feedxthe-crusher wheel slowly towards the grind- ,i lgwheel. V g

'7. A grinding machine ,having a frame carrying a rotatable grinding wheel and drive means therefor, a :-rotatable crusher wheel, a crusher when support slidably guided on the machine frame-and comprising a bracket movable towards ,and from the grinding wheel axis and a reciprocaibly operable carrier slidabl guided on the machine frame :formovement towardsand from the grinding wheel axis and slidably supporting said bracket, power means for reciprocating said car.- ;rier on said frame, a-threadedinterconnection betweenthe carrier and the bracket, means for man-- ,ually operatingsaid interconnection, and a con nection to said power means for automatically operating saidinterconnection to feed. the crusher wheel intothe grinding wheel.

8. .-A.grinding machine having a frame carry- ,ing a rotatable grinding wheel and drive means therefor, .a rotatable crusher wheel, a crusher Vi/T111681 support movably carried by the machine framefladjusting mechanism for said support, an adjusting motor for operating said adjusting mechanism, said adjusting mechanism including a deed-screw :and a pawl and ratchet forzsaid feediscremand means operated by said adjusting motor to move the crusher wheel support towards the grinding wheel and subsequently operate the pawl. and ratchet to feed the crusher wheel into the grinding wheel.

QVA grinding machine having a frame carrying la-rotatable grinding wheel, power means for rotating the grinding wheel at a speed less than atnormal grinding speed, a rotatable crushler wheel,a crusher wheel support movalbly carried by the machine frame, adjusting mechanism for said support, an adjusting motor for operating said adjusting mechanism to move the crusher wheelto the grinding wheeland means controlled bysaid adjusting motor to operate said power .meansafterthe crusher wheel is'moved into con- ,tact with the grinder wheel.

10., A grinding machine having a frame carrying-arotatable grinding wheel, power means for rotating the grinding wheel-at a speed less than :a vnormal grinding. speed, a rotatable crusher wheel, a crusher wheel support movably carried ,by the frame, an adjusting motor, meansoperated why saidLadjusting, motor to :move' the .crusher wheel support rapidly :towardslthe-grinding wheel, to initiate slow speed operation 'of thegrinding wheel by said power means, to then movethe crusher wheel slowly to the grinding wheel-and to then retract it from the grinding wheel, means for manually moving the crusher wheel towards the grinding wheel, and means to stop thesmotor controlled movements-of the crusher wheel while the power means is-rotating the grinding wheel topermit movements of the crusher wheel underl manual control. 1

ll. Ina grinding machine having a frame'carrying a rotatable grinding wheel, driving means for said grinding wheel, a rotatable crusher wheel, a crusher wheel support movably carried by said frame, a carrier movably mounted, on said frame and carrying the crusher wheel support, adjusting mechanism for varying theposition of said support on thecarrier, additionaladjusting mechanism for varying the position of the carrier on the frame, an adjusting motor for operating said adjusting mechanism, means for varying the amount of movement of the crusher wheel support, and indicating means forshowing the position of the crusherwheel.

12. A grinding machine having aframe icarrying a rotatable grinding wheel, driving means for operating-said grinding wheeliat a speed less than a normal grinding speed, a rotatable crusher wheel, a crusher wheel support movably carried by the-frame, a power source, adjusting mechanism operated from said-source to advance the crusher wheel support towards thegrinding wheel, means operable at the completion of such movement toinitiate operation of said drivingmeans, means including a power operatedadjusting-screw for positively feeding the crusher wheel support slowly toward the grinding wheel during operation of said driving means, and means for stopping feeding movement of the crusherwheel support during continued operation of said driving means before thecrusher wheel support is retracted.

13.- A grinding machine having a frame carrying a rotatable grinding wheel, driving means-for operating said grinding wheel at a speed less than ancrmal grinding speed,.a rotatable crusher wheel, a crusher wheel support movably carried by the frame, a power source, adjusting mechaoperated from said source to advance the crusher wheel support rapidly towards the grinding wheel, means operable at the completion of the rapid movement of the crusher wheel support to initiate operation of saiddriving means, means includinga power operated adjusting screw for positively feeding the crusher wheel towards the grinding wheel slowly during the-operation of said driving means, power'operated means for retracting the crusher wheel support, and means insuring a delay after completionofwth feeding movement of the crusher wheel before retraction wheel and the grinding wheel, then maintain the axes of the grinding wheel and the crusher wheel at a fixed spacing during continued operation of the driving means and then separate the crusher wheel and the grinding wheel.

15. A grinding machine having a frame carrying a rotatable grinding wheel, driving means for operating said grinding wheel at a speed less than a normal grinding speed, a rotatable crusher wheel, a crusher wheel support movable relatively to the grinding wheel in a direction to vary the distance between the axes of the crusher wheel and the grinding wheel, and means for automatically in timed sequence first moving the crusher wheel support and grinding wheel relatively to cause approach of the axes of said wheels and then initiate operation of said driving means.

16. A grinding machine having a frame carrying a rotatable grinding wheel, driving means for operating said grinding wheel at a speed less than a normal grinding speed, a rotatable crusher wheel and means for automatically and sequentially causing approach of the axes of said wheels at a comparatively rapid rate, then initiate operation of said driving means, and then causing further approach of the axes of said wheels at a' comparatively slow rate.

17. A grinding machine having a frame carrying a rotatable grinding wheel, driving means for operating said grinding wheel at a speed less than a normal grinding speed, a rotatable crusher wheel, a crusher wheel support carried by said frame, power means for adjusting said crusher wheel support relatively to the grinding wheel axis and in a direction towards and from the grinding wheel, a positive mechanical operating device for moving the crusher wheel support, and means operable to cause said power means to carry out a cycle of operations to sequentially cause the crusher support to be moved towards the grinding wheel at a comparatively rapid rate, then cause operation of said mechanical interconnection to move the crusher support at a comparatively slow rate, and then maintain the axes of said wheels with a fixed spacing and then separating the crusher wheel from the grinding wheel.

18. A grinding machine having a frame carrying a rotatable grinding wheel, driving means for operating said grinding wheel at a speed less than a normal grinding speed, a rotatable crusher wheel, a crusher wheel support, a slide mounted on said frame for movement towards and from the grinding wheel and carrying said crusher wheel support for movement thereon towards and from the grinding wheel, power means for adjusting said crusher wheel support on said slide and for adjusting said slide on said frame, and means controlling said power means to sequentially move the crusher wheel support rapidly towards the grinding wheel, then initiate operation of said-driving means, then feed said support slowly towards the grinding wheel, then maintain the grinding wheel support in fixed position during continued operation of the driving means and then retract the crusher wheel support.

LOUIS F. POLK. 

